1-To make the crust place whole Oreo: To make the crust place whole Oreo cookies with the filling in a food processor and ground in fine crumbs. Stir in melted butter and press the mixture into the bottom of the 13 x 9-inch casserole dish. Place in the fridge or freezer to firm while making the next layer.
2-To make Hot Chocolate Cheesecake Mousse Layer,: To make Hot Chocolate Cheesecake Mousse Layer, beat softened butter and cream cheese with vanilla and powdered sugar until creamy and smooth.
3-In another bowl beat heavy whipping cream: In another bowl beat heavy whipping cream and instant milk chocolate powder until stiff peaks form. Fold half of the hot chocolate whipped cream in the cheesecake mixture, then fold in another half, Scrape the bottom of the bowl to incorporate everything well. Then, spread over the crust and set in the fridge or freezer to firm.
4-For pudding layer in a bowl whisk: For pudding layer in a bowl whisk instant chocolate pudding mix and milk until it starts thickening. Stir in mini marshmallows and spread over a hot chocolate mousse layer. Place it in the fridge or freezer to set.
5-When the pudding layer has set, make: When the pudding layer has set, make whipped cream. Beat heavy whipping cream and powdered sugar until stiff peaks form. Spread whipped cream on top of the pudding layer and place in the fridge for a few hours or better overnight.
6-Before serving scatter 2 cups of mini: Before serving scatter 2 cups of mini marshmallows over whipped cream.
7-Serve drizzled with melted chocolate, Nutella, or: Serve drizzled with melted chocolate, Nutella, or chocolate topping.
8-Store leftovers in the fridge: Store leftovers in the fridge.